Do not remove blockingpage.css from existing installations as some users might use them for custom.php

Signed-off-by: Christian König <ckoenig@posteo.de>

automated install/basic-install.sh

@@ -1671,11 +1671,6 @@ installPiholeWeb() {
     # and the 404 handler
     install -D -m 644 ${PI_HOLE_LOCAL_REPO}/advanced/index.php ${PI_HOLE_404_DIR}/
 
-    # Remove superseded file
-    if [[ -e "${PI_HOLE_404_DIR}/blockingpage.css" ]]; then
-        rm "${PI_HOLE_404_DIR}/blockingpage.css"
-    fi
-
     printf "%b  %b %s\\n" "${OVER}" "${TICK}" "${str}"
 
     local str="Backing up index.lighttpd.html"